31 tools · Unit Converters
Unit Converters tools
Length, speed, temperature, and more — no ads, no math.
Popular in unit converters
Unit Converters
Unit Converter
Convert length, weight, volume, area, speed, energy, and more with this free online tool. All common units in one place, no registration needed.
Unit Converters
Temperature Converter
Convert between Celsius, Fahrenheit, and Kelvin instantly. Live conversion as you type.
Unit Converters
Length Converter
Convert length units: meters, feet, inches, miles, kilometers, yards. Fast, free, and mobile-friendly.
Unit Converters
Speed Converter
Convert between mph, km/h, m/s, knots, and feet per second. Free online speed converter with live conversion and no ads — usable instantly in your browser.
Unit Converters
Age Calculator
Calculate exact age in years, months, and days from any birth date to any target date.
Unit Converters
Weight Converter
Convert between kilograms, pounds, ounces, grams, stones, and tons. Instant, free, mobile-friendly.
More unit converters tools
- Time ConverterTransform time units between seconds, minutes, hours, days, weeks, months, and years instantly. Perfect for time logs and billing with no sign-up.
- Area ConverterConvert between square feet, square meters, acres, hectares, square yards, square miles. Free, fast.
- Volume ConverterConvert between liters, gallons (US/UK), cups, milliliters, pints, and cubic meters instantly online. A free converter with no sign-up, ready in your browser.
- Data Size ConverterConvert between all data storage units, from bytes to petabytes, in both binary and decimal formats. Get instant results online, free, no signup.
- Energy ConverterConvert between joules, calories, kilowatt-hours, and BTUs instantly in your browser. A free online tool with no sign-up or download required.
- Fraction CalculatorAdd, subtract, multiply, or divide fractions — with simplified results and mixed-number conversion. Free math tool.
- Average CalculatorPaste a list of numbers and get the mean, median, mode, range, and sum. Free statistics helper.
- Sample Size CalculatorCalculate the minimum sample size for any proportion at your chosen confidence level and margin of error. Finite-population correction. Free, no sign-up online.
- Standard Deviation CalculatorCalculate sample (n−1) and population (n) standard deviation and variance side by side. Paste any list of numbers. Free, instant, browser-only, no sign-up.
- P-Value CalculatorConvert any z- or t-statistic into a one- or two-tailed p-value instantly. Significance flagged at α = 0.10, 0.05, 0.01. Free online tool, no sign-up needed.
- Correlation CalculatorCompute Pearson's r between two paired number lists, plus r² and the t-statistic for testing rho = 0. Free online calculator with verbal interpretation.
- Scientific Notation ConverterConvert between decimal, scientific (a × 10ⁿ), and engineering (multiple-of-3 exponent) notation in one tap. SI-prefix friendly. Free, instant, no sign-up.
- Equation SolverSolve ax+b=0, ax²+bx+c=0, and ax³+bx²+cx+d=0 instantly. Free online solver with discriminant analysis and complex roots in a+bi form. No sign-up.
- Derivative CalculatorSymbolic derivative for polynomials in x. Free online tool that accepts 3x^2 + 2x - 5 style input and returns f'(x) in pretty form instantly. No sign-up.
- Vector CalculatorCalculate 2D and 3D vector math: magnitude, normalize, sum, dot, cross, and angle between. Built for physics and graphics work. Free, instant, no sign-up.
- Projectile Motion CalculatorCalculate time of flight, range, max height, and impact velocity for 2D projectile motion under gravity. SVG trajectory included. Free, instant, no sign-up.
- Matrix Determinant CalculatorCalculate determinants for square matrices 2×2 to 6×6 instantly. Direct formulas, Laplace expansion, singular detection. Free, no sign-up, browser-only.
- Molar Mass CalculatorCalculate molar mass instantly from any chemical formula. Get an element-by-element breakdown, supports nested parentheses and hydrates, using IUPAC 2024 atomic masses online.
- Molarity CalculatorCalculate molarity, mass, or volume of any solution using M = moles/liters. Built for lab prep and stoichiometry homework. Free, instant, no sign-up needed.
- Dilution CalculatorSolve for any of C₁, V₁, C₂, V₂ using the dilution equation. Free online calculator that includes the solvent volume needed for the diluent. No sign-up.
- pH CalculatorConvert between pH, pOH, [H⁺], and [OH⁻] at 25°C in one click. Color spectrum shows acidic, neutral, or basic instantly. Free, browser-only, no sign-up.
- Date Difference CalculatorCalculate the exact number of days, weeks, months, or years between any two dates instantly. A free, private, and mobile-friendly online calculator.
- Time Duration CalculatorCalculate the precise hours, minutes, and seconds between two times. Essential for timesheets and podcasts, available online for free with no download.
- Prime Number CheckerTest any number for primality and find all its factors instantly in your browser. Free, no-registration tool for fast math checks.
- Ratio CalculatorSimplify, compare, and scale ratios for recipes, mixing, or design work. This free online ratio calculator works instantly with no signup or download needed.
Guides about unit converters
Guide · Unit Converters
How to calculate days between two dates
Calendar, business, and trading days, inclusive/exclusive endpoints, leap years, 30/360, time-zone gotchas, ISO format tips. Free online guide. No sign-up.
Guide · Unit Converters
How to convert between units
Quickly convert length, weight, volume, and temperature with offset math. Free, instant guide clarifies US vs UK gallons, data sizes, and ton variants.
Guide · Unit Converters
How to convert between speed units
Unit families, conversion factors, pace vs speed, context per unit, significant figures, Beaufort scale, common mistakes. Free online guide. No sign-up.
Guide · Unit Converters
How to read Roman numerals
Parse seven letter values, subtractive rule, and large-number edge cases free online. Convert Roman numerals to numbers instantly with no signup required.
Guide · Unit Converters
How to calculate ratios
Learn part-to-part vs part-to-whole, GCD simplification, scaling recipes, cross-multiplication, and common ratio traps in word problems. Free, no sign-up read.
Guide · Unit Converters
How to work with fractions
Find common denominators, convert mixed vs improper, multiply, divide, and simplify with GCD. Free online fractions guide with instant examples. No signup.
Guide · Unit Converters
How to calculate averages
Arithmetic mean, weighted mean, median vs mode, geometric and harmonic means, when each is right, and why mean misleads. Free online guide. No sign-up.
Guide · Unit Converters
How to convert temperatures
Three scales, conversion formulas, why the offset matters (unlike length), absolute zero, and quick mental math for °C ↔ °F. Free online guide. No signup.
Guide · Unit Converters
How to convert length units
Convert meters to feet and more online instantly. Free length unit converter for construction and travel with no download needed.